Dehydrohalogenation process and catalyst



United States Patent 3,341,616 DEHYDRGHALOGENATION PROCESS AND CATALYSTVan C. Vives, Bartlesville, 01412., assignor to Phillips Petroleum(Iompany, a corporation of Delaware No Drawing. Filed Jan. 10, 1966,Ser. No. 519,446 Claims. (Cl. 260677) This invention relates to enationof novel catalyst comprising a borate to produce olefins wherein the Iormation of branched-chain olefins through isomerization is minimized.In accordance with a further aspect, this invention relates to acatalyst composition comprising an alkali metal salt of a boric acid anddiatomaceous earth that is efiective for dehydrohalogenating a kylhalides or producing linear olefins With high selectivity andconversion.

Currently, considerable interest and much research effort have beendevoted to the production of biodegradable detergents. proposed methodcomprises halogenating produced olefins is the result. While, for someuses, this are of little value when an object of this invention is toprovide an improved process for the dehydrohalogenation of halogenatedhydrocarbons whereby the prior art problems of isomerization and/orcracking are obviated.

Another object of this invention is to provide a process for thedehydrohalogenation of straight-chain alkyl halides to produce With ahigh degree of selectivity straightchain olefins Another object of thisinvention is to provide a process for the dehydrohalogenation of alkylhalides to produce olefins wherein the formation of branched-chainolefins through isomerization is minimized.

Another object of this invention is to provide an improveddehydrohalogenation catalyst.

Other aspects, objects,

In accordance With my invention, unsaturated hydrocarbons are producedby the dehydrohalogenation of halmaceous earth and an alkali Inaccordance with one embodiment of my invention, olefins are produced bythe dehydroha'logenation of alkyl halides over a catalyst comprisingdiatomaceous earth and an alkali metal salt of a boric acid, i.e., analkali metal borate. The use of this catalyst results in high conversionof the alkyl halides, with high selectivity to the desired olefins.Furthermore, little or no cracking, skeletal isomerization, or otherside reaction occurs. The process of the invention ployed in the 20solution of the alkali metal salt in a halogenated alkanes, includingmonois especially useful in the production of linear olefins from linearalkyl halides, for example, in the production of biodegradable detergentalkylate, in which skeletal isomen'zation to branched-chain olefins isespecially undesirable.

Examples of representative alkali metal salts of a boric acid which canbe employed according to the invention can be employed according to theinvention, those preferred are the sodium and potassium salts oftetraboric acid.

The alkali metal salt of the boric acid that can be emwater. a mineralacid sequent volatilization of the is desirable to add In someinstances, it to achieve complete minimum amount of solvent.

Although the concentration of the alkali metal salt in the diatomaceousearth can vary appreciably, the alkali metal salt will generallycomprise about 05-30 weight percent of the catalyst, usually comprisingabout 1-20 Weight percent of the catalyst, these concentrations beingbased on the alkali metal salt in its anhydrous form. The particle sizeof the borate-diatomaceous earth catalyst bed type dehydrohalogenationprocess reactions.

The catalysts of my invention are suitable for the dehydrohalogenationof halogenated hydrocarbons broadly, and is particularly suitable fordehydrohalogenation of and polyhalo substituted alkanes of thestraight-chain, branched-chain and cyclic type. The invention isparticularly suitable to the dehydrohalogenation of straight-chain alkylhalides to produce straight-chain olefins.

The alkyl halides employed in the dehydrohalogenation process are alkylhalides, generally containing from 4 to 18 carbon atoms per molecule.The alkyl halides can be chlorides, iodides, bromides, fluorides, ormixtures thereof. However, the invention is particularly applicable tothe dehydrohalogenation of alkyl chlorides.

Representative examples of applicable alkyl halides having 4 to 18carbon atoms are:

l-chloro'butan'e 2-bromopentane l-iodohexane 3-iodooctane Z-fluorononane3-fiuorooctane l-chlorononane l-chlorododecane 2-bromodecanel-chloropentadecane -l-chlorooctadecane 1,4-dichlorobutanel-chloro-3-methyl-butane l bromo-4 methyloctane 2-chloro-5-ethyldodecane1,3,5-trichlorodecane prising product olefin and unconverted alkylhalides can 1,3,4,7-tetrachlor-otetradecane be passed from the firstdistillation zone to a second disand the like. tillation zone whereinthe product olefins are separated Examples of some olefins which can beproduced by from the unconverted alkyl halides. The separated alkyl theprocess of this invention include: 5 halides can be recycled to thedehydrohalogenation zone. l-butene In carrying out the invention whenthe dehydrohalo- 2-pentene genation process is conducted in the vaporphase, the del-hexene hydrohalo-genation zone vapor effluent can bepartially 3-octene 7 condensed to separatevthe hydrogen halide therefromand l-decene 10 the condensed liquid fraction pased to a distillationzone 2-dodecene wherein the product olefins are separated from theunl-pentadecene converted alkyl halides.

l-octadecene 3-rnethyll-butene 4-methyl-1-octene 5 -ethyl-2-dodecene PLEand the like.

The vapor-phase dehydrochlorination of a mixture of Thedehydrohalogenation ro e i ndu t d t a isomeric linear monochlorononaneswas carried out in a temperature of from about 150 to bout 600 (3,, r ftubular reactor under various catalytic conditions at atably within therange of about 250-450 C. The flow mosph Pressure and at temperaturesranging from rate of the halogenated compound to be dehydrohalogen- 250C(to 400 C. The liq i hourly space Velocity ated over the catalyst,based on the halogenated com- (LHSV) f h m n hl ron n nes r nge from0.57 to pound in its liquid state, generally ranges from about 0.1- 1.1volumes of liquid chlorides per-volume of catalyst per 5, preferablyabout 0.3-3, volumes per volume of catalyst hour. The catalystscontaining an alkali metal tetraborate per hour. Although the reactioncan be carried out in the r p p y i g crushed Celite 408 /16 i liquidphase, it is preferably arried out in the vapor ha e, pellets ofdiatomaceous earth from Johns-ManvilleCorp.) The reaction pressure isordinarily atmospheric or lower; attapulgite, or Fullers earth with therequired amount of however higher ressures, for example, up to about 100alkali metal 161131301 ate in 811111616111; water to thoroughlyp.s.i.g., can be employed. If desired, anon-reactive diluent Wet theCelite attapulgite, 0T earth, after such as nitrogen, or other inertgas, or a parafiinic hydrowhich the water was removed byvolatilizationThe catcarbon can be present. alysts containing zincborate, boron phosphate, or sodium The dehydrohalogenation process ofthe invention can hydroxide were prepared similarly. When lithiumtetraborbe conducted as a batch or continuous process, utilizing ate orzinc borate was employed, sufficient hydrochloric either liquid phase orvapor phase operation. A preferred 5 acid was added to the aqueousmixture to achieve solution method of operation is to pass thevolatilized alkyl halide of the boron-containing compound; boronphosphate was through abed of the borate-diatomaceous earth catalyst ofdd d as a Suspension t h C m 403 Th other k y invention 31 a rate chosento p v desired degree metal tetraborates and sodium hydroxide were usedas of conversion with a high selectivity for the desired oletheiraqueous Solutions The m t f the dehydm fimc matena1' unconverted mammalbe swaraied to chlorination reactor was passed into water. After the a ag' Zone efliltllentvby Fonventlonal separatlon efiiuent and water werethoroughly shaken to remove hymet 0 s an recycled to e reaction ZoneFurthermore drogen chloride from the organic phase, the organic phase asactivity of the catalyst decreases, operation at successively highertemperatures can be employed until regeneration of the catalyst isrequired.

In actual operation wherem the dehydrohalogenation was separated andanalyzed bygas chromatography. The reaction conditions and results aresummarized in the following table, together with those for anon-catalyzed process is conducted in the liquid phase, thedehydrohaloreaction The fl hourly 5Pace 7 of genation zone liquidefiiuent can be passed to a first dis- Chlofononane? the nofl-catalyzedfeactwn 1S given as tillation zone wherein dissolved hydrogen halideissep- VOlumeSOf q 'chlorldes P Volume of reactor P arated from theliquid eflluent. The liquid fraction comhour.

' TABLE* I Selectivities, mole percent Catalyst Temp,. LEISV, vol./-Conversion C voL/hr. 01 0 1511 01 Light Linear Other Olefinlc IsoolefinsOlefins Products Products 1 525 3. 8 92. 2 4. 9 0 92. 9 2. 2-- 275 0.8563.9 1.0 10. 5 88. 5 0 275 0. 92 99. 3 4. 7 a0. 3 e4. 5 0. 5 275 0. 99.5 8. 1 34. 5 56. 2 1. 2 250 1. 1 99. 5 1. 0 28. 3 09. 4 1. 3 6--- 3001.0 96.6 0 16.5 83.5 0 7. Celite 408/10 Wt ercent LizB4O1fi. 275 0. 9675. 5 0 0. 3 99.7 0 8. Celite 408/26 wt. percent NazB4O1 350 0. 91 84. 50 1. 4 98. 6 0 :9. Oelite 408/53 wt. percent NazBtOL 250 0.75 81.1 0 0.6 99. 4 0 10- o 350 0.89 94. 2 0 0. 6 99. 4 0 .11.- do 400 0. 57 90.8 00.9 98. 5 0.6 12- Celite 408/106 wt. percent Na2B4O 400 0. 68 92. 8 0 0.6 99. 4 0 13- Celite 408/53 wt. percent KzB4O- 350 0. 71 77. 8 0 1. 099. 0 0 14 -do 400 0. 66 83. 5 0 0. 7 09. 3 0 Celite 408/76 Wt. percentKzBtO 275 0. 84 88. 8 0 0 0 Celite 408/10 wt. percent Zna(BOz)s.- 275 0.85 95. 1 5. 1 25. 8 69. 1 0 Celite 408/10 Wt. percent BPO4 275 0.83 78.9 0 2. 7 97.3 0 Attapulgite/7.6 wt. percent K B O 250 0.80 98. 8 3. 541.8 53. 4 1. 3 Fullers earth/7.6 wt. percent KeB O1 250 0.79 97. 3 0.414. 8 83. 3 l. 5 Celite 408/50 Wt. percent NaOH 400 0.72 99. 6 0. 7 22.7 74. 6 2. 0 Celite 408/10 Wt percent NaOH 400 0. 77 99. 4 0. 4 19. 579. 5 0. 6

'fThe mixture of llnerar monochlo'rononanes used in runs 4, 5, 9, 15,18, and 19 was made up of 95.4 weight percent secondary and 4.6 wicghtpercent P Y chlorides; in a l other runs the mixture was made up of 86.4weight percent secondary and 13.6 weight percent primary chlorides.

Runs 7-15 in the above table, according to the invention, demonstratethe high selectivity to linear olefins obtained by dehydrochlorinationin the presence of an alkali metal tetraborate on Celite 408. Little orno cracking, skeletal isomerization, or other side reaction occurred. Acomparison of runs 15-17 shows that use of other types ofboron-containing compounds resulted in inferior selectivity to linearolefins. Runs 18 and 19 show that unsatisfactory selectivity wasobtained when potassium tetraborate on attapulgite or Fullers earth wasused, and runs 20 and 21 demonstrate unsatisfactory selectivity whensodium hydroxide on Celite 408 was used. Runs 2-6 show that Celite 408and related substances, when used alone, did not efiFect satisfactoryselectivity to the desired linear olefins. Run 1 shows thatunsatisfactory selectivity was obtained in the absence of a catalyst.

Reasonable variation and modification are possible within the scope ofthe foregoing disclosure and the appended claims to the invention, theessence of which is a process for dehydrohalogenating a halogenatedcompound to selectively produce the desired unsaturated compound at highconversion in the presence of a novel catalyst comprising an alkalimetal borate and diatomaceous earth.

1 claim:

1. A catalyst composition comprising an alkali metal salt of boric acidand diatomaceous earth.

2. A catalyst composition according to claim 1 wherein the amount ofsaid alkali metal salt comprises about 0.5- 30 weight percent of saidcatalyst.

3. A catalyst composition according to claim 1 wherein said alkali metalsalt is sodium tetra-borate.

4. A catalyst composition according to claim 1 wherein said alkali metalsalt is potassium tetraborate.

5. A catalyst composition according to claim 1. wherein said alkalimetal salt is lithium tetraborate.

6. A process for preparing aliphatically unsaturated hydrocarbons bydehydrohalo-genation which comprises contacting a halogenatedhydrocarbon compound with a catalyst composition comprising an alkalimetal salt of boric acid and diatomaceous earth.

7. The process of claim 6 wherein the quantity of said alkali metal saltis in the range of 0.5 to 30 weight percent of said catalyst.

8. The process of said contacting is conducted range of about to 600 C.

9. A process according to claim 6 for producing linear olefins with highselectivity and conversion wherein said halogenated hydrocarbon compoundis an alkyl halide having from 4 to 18 carbon atoms per molecule.

10. A process according to claim 9 wherein said alkyl halide ismonochloronane and wherein said alkali metal salt is selected fromlithium tetraborate, sodium tetraborate, and potassium tetraborate.

claim 6 wherein the temperature of at a temperature in the ReferencesCited UNITED STATES PATENTS DELBERT E. GANTZ, Primary Examiner. G. E.SCHMITKONS, Assistant Examiner.

1. A CATALYST COMPOSITION COMPRISING AN ALKALI METAL SALT OF BORIC ACIDAND DIATOMACEOUS EARTH.
 6. A PROCESS FOR PREPARING ALIPHATICALLYUNSATURATED HYDROCARBONS BY DEHYDROHALOGENATION WHICH COMPRISESCONTACTING A HALOGENATED HYDROCARBON COMPOUND WITH A CATALYSTCOMPOSITION COMPRISING AN ALKALI METAL SALT OF BORIC ACID ANDDIATOMACEOUS EARTH.